function updateProgress() {
    const zhuCheckbox = document.getElementById('zhuCheckbox');
    const tiaoCheckbox = document.getElementById('tiaoCheckbox');
    const paoCheckbox = document.getElementById('paoCheckbox');
    const progressBar = document.getElementById('progressBar');

    let completedSteps = 0;
    if (zhuCheckbox.checked) {
        completedSteps++;
    }
    if (tiaoCheckbox.checked) {
        completedSteps++;
    }
    if (paoCheckbox.checked) {
        completedSteps++;
    }

    progressBar.value = completedSteps;

    // 检查是否所有步骤都已完成
    if (completedSteps === 3) {
        document.body.style.backgroundImage = "url('bg2.jpg')";
    } else {
        document.body.style.backgroundImage = "url('bg.png')";
    }
}